PSQ has so far been researched in many cases. For example, the general remark of PSQ written by Baney et al. is described in Chem. Rev. 1995, 95, 1409. According to this, confirmed to be present is PSQ having a structure such as an amorphous structure showing no fixed structure in addition to a ladder structure, a completely condensed structure and an incompletely condensed structure. The completely condensed structure comprises plural cyclic structures, and is a structure forming a closed space. And the form of the closed space is not restricted. The incompletely condensed structure shows a structure in which at least one portion in the completely condensed structure is not shut and in which a space is not closed.
Feher et al. obtained PSQ of an incompletely condensed structure by hydrolyzing cyclopentyltrichlorosilane or cyclohexyltrichlorosilane in acetone (Organometallics, 1991, 10, 2556). Shchegolikhina et al. synthesized PSQ of a cyclic tetramer in which a terminal was turned into Si—O—Na by hydrolyzing phenyltributoxysilane in butanol using an equivalent mole of sodium hydroxide and an equivalent mole of water. Further, they synthesized PSQ of a cyclic tetramer in which a terminal was turned into Si—O—Na by reacting phenyltrichlorosilane-hydrolyzed product with an equivalent mole of sodium hydroxide in butanol (Organometallics, 2000, 19, 1077).
However, reported have been no examples in which PSQ having a completely condensed structure or an incompletely condensed structure is synthesized using the method of Shchegolikhina et al. Further, among PSQ having a completely condensed structure or an incompletely condensed structure, the kind of the compounds which are readily synthesized and isolated is restricted. Among them, the number of the commercially available compounds is further restricted. In recent years, PSQ derivatives obtained by introducing various functional groups into PSQ having a completely condensed structure or an incompletely condensed structure are commercially available from Hybrid Plastic Co., Ltd., and many uses are proposed.
However, the commercially available PSQ derivatives have only several kinds of fundamental skeletons including the skeletons having an organic silicon group of a bonding state other than SiO3/2. Accordingly, that PSQ derivatives having a novel skeleton are provided is desirable in order to effectively make the best use of a PSQ derivative having a completely condensed structure or an incompletely condensed structure in wide uses. It is important as well that they can be produced at a lower cost for further shorter time as compared with in the past. Further, the existing PSQ derivatives have had the problems that they have an inferior compatibility with resins and therefore can not uniformly be mixed and that they are whitened when forming a coating film or bled out from a coating film, so that the addition amount is restricted. Accordingly, some of them could not sufficiently provide characteristics expected to PSQ. Hence, it is desirable for expanding the uses of PSQ, to provide a PSQ derivative which is improved in a compatibility with resins. The subject of the present invention is to solve the above problems on conventional silsesquioxanes by providing a novel PSQ derivative and a process for producing the same at a lower cost for shorter time.